Continuous chrome mordanting and dyeing of wool



Feb. 17, 1953 J. N. 'DALTON ETAL 2,628,383

CONTINUOUS CHROME MORDANTING AND DYEING OF WOOL Filed Nov. 23, 1949lA/l/E/V 7'055' JO NMDALTOM Jam/PP 11511055 ATToR/vEV contrasted whichhave become available, such as the meta- Patented Feb. 17, 1953 UNITEDSTATES PATENT OFFICE CONTINUOUS CHROME MORDANTING AND DYEING F WOOL JohnN. Dalton, Providence, R. I., and John P. Ploubides, Lawrence, Mass.,assignors to Pacific Mills, Lawrence, Mass, a corporation ofMassachusetts Application November 23, 1949, Serial No. 129,146

2 Claims. (Cl. 8-99) "and scouring which characterizes the bottom chromemethod, but at a cost which is much less than the cost of mordanting bythe conventional bottom chrome methods.

It is well known that the old bottom chrome method, i. e., applicationof the mordant in a separate bath before the cloth is dyed gives asuperior quality dyeing. This method. however, has the disadvantage ofmuch higher cost as with other mordanting methods chrome and top chromemethods, with the result that the older bottom chrome method has almostentirely gone out of use. However, with these more recent methods,dyeings of inferior quality are often obtained due to a poor penetrationand lack of solidity of color, which is caused by formation of achrome-dye complex in the bath.

This invention has as an object to provide a process for mordanting woolpiece goods which will be comparable, in the quality of the resultingdyeings, with the conventional bottom chrome method but yet will be lesstime-contrivalent chromium compound by passing the cloth from thepadinto a hot acid bath to thoroughly soak the impregnated cloth withthe acid solution, alternately and repeatedly exposing the cloth tosteam and immersing it in the acid bath, then exposing the cloth, stillwet with acid solution, for a substantial timeinterval to an atmosphereof steam and finally at least partially neutralizing the acid by runningthe cloth through a mild'alkaline bath or thoroughly washing it withwater, all as the cloth is maintained continuously in motionv We havevfound that this treatment leaves the cloth in condition to beimmediately dyed with a mor- 'dant acid dye. g V

One feature of our invention is the processing of the cloth as it iskept in continuous motion through the equipment by first padding it witha Wetting agent along with the unreduced mordant and thereafterthoroughly soaking it with acid before and after repeated exposure ofthe cloth to steam.

The accompanying drawing is a schematic illustration of representativeapparatus in which our process can be carried out.

Referring to the drawing, the undyed cloth 2, in open width suitablyprepared for mordanting and dyeing, is supplied to a conventional padmangle which preferably is a three-bowl padder, the trough e of which isfilled with an aqueous solution at F. to 212 F. containing a wettingagent and about 0.25% to 1.0% of its weight of sodium bichromate orother suitable mordanting agent. Several pieces of goods may be sewedtogether end-to-end to form a long length of cloth to be supplied to thepadder. On entering the padder, the cloth is first immersed in theliquid bath by its passage about the roller 8, then is squeezed in thenip of rolls l0 and I2, again immersed in the liquid by its passageabout a set of rollers I4 and finally led out of the bath over the guideroller l6 and through the nip of rolls l8 and I0, where its final liquidcontent is determined by the setting of the rolls.

From the pad mangle the cloth passes without interruption of itsmovement into a steam "box 251 where the operation of reducing thechromium compound to a trivalent chromium compound is carried out bysoaking the cloth with ahot acid liquid and alternately immersing it inthis liquid and steaming it, followed by substantial exposure to steam.The lower part of the steam box 26 is divided into three approximatelyequal sized, open-topped compartments 22, 24 and 26 by lowpartitions 2Band 3B. The cloth is led through the steam box 25 over a series of upperguide rolls 32 and a series of lower guide rolls 34 as shown.

Compartment 22 is filled with an acid solution maintained at atemperature in the range F. to 212 F. by steam which enters thecompartment at any suitable point below the liquid level therein, asfrom steam supply pipe 2|.

On entering the steam box 26 the cloth is immediately led downwardlyabout guide roll 36 to immerse it in the acid solution in compartment22, with which solution the Web of cloth is 'immediately soaked in itspassage about guide roll 3 36 and the first of the series of lower guiderolls 34.

The cloth then passes alternately over an upper guide roll 32 and undera lower guide roll 34 so that it is alternately and repeatedly immersedin the acid liquid in compartment 22 and exposed to the steam atmospherein the upper part of the steam box provided by steam from steam supplypipe 2!.

The cloth next passes in the same manner through compartment 24, whichcontains steam at atmospheric pressure but no liquid, so that the clothis exposed to a steam atmosphere for a substantial period of time.

Next the cloth passes through compartment 26 which contains water whichoperates as a liquid seal and finally, the cloth emerges from steam boxat 38 and is passed between the squeeze rolls 40.

The traveling cloth then passes over guide rolls 42 and through washboxes Ml, 48 in which its acidity is reduced by washing with water.Desirably the water in the first wash box 44 may contain a mild alkali,such as diammonium phosphate, to accelerate the neutralization of theliquid content of the cloth.

The cloth on leaving the first wash box is passed through a pair ofsqueeze rolls 43 into the wash box 46, is given a final squeeze at 50 asit leaves box 06, and is then collected in any suitable manner at 52 asby passing it into a scray. The cloth then may be taken directly to thedye vat for dyeing.

The following examples of particular process conditions and particulardyestuffs are given as illustrative of the invention.

Example I One out of worsted gabardine yards in -length and 65" wide wascontinuously chrome mordanted by our process employing sodium bichromateand 0.5% of an alkylarylpolyether in the initial impregnating bath and2% hydroxyacetic acid as the reducing solution. The material was allowedto remain within the chamber for 1 to 1 /2 minutes, and was thenneutralized to a pH of 5.7 in a continuous open width washer with tapWater. The material was then dyed with the following color combination:

Color Index No., Pro- A comparable sample of the same gabardine materialwas mordanted by the conventional 'bottom chrome method, that is byboiling it in a kettle containing a bath of sodium bichromate and thendyed with the same color combination. The dyeing of the cloth mordantedby the process of Example I was of superior quality, having as goodlevelness and color solidity as the sample mordanted by the conventionalbottom chrome method.

fulling and to scouring as compared with the sample mordanted by theconventional bottom chrome method. In the dyeing of the sample-mordanted by our process, 10% greater exhaus- In addition the samplemordanted by our process showed increased fastness both to tion wasobtained than in the dyeing of the conventional sample.

Example II The procedure of Example I was repeated, with two identicalsamples of cloth, employing as the dyestufi:

Color Index No., or

Dye Vendor Amount Per Cent Eriochrome Blue Black R 0. Acid AlizarineViolet N. Anthraquinone Violet 3R Xvlene Milling Blue FF Metomega ChromeGrey GL. Wool Fast Blue Color Index No. 202. Color Index No. 169. ColorIndex No. 1080. Sandoz.

Do. Color Index No. 833.

' sults as to processing speed and quality of the dyeing are obtained bythe use as a wetting agent of an alkylarylpolyether alcohol which may bepresent in the pad mangle in an amount of the order of about 0.5% byweight of the entire solution.

As the acid for reducing the chrome, we prefer hydroxyacetic acidbecause it contributes to the effectiveness and speed of our continuousprocess by virtue of its high reducing power in proportion to its acidvalue, permitting rapid passage of the cloth with rap-id reduction ofthe chrome without significant deleterious efiects on the wool substancedue to acidity.

The pressure of the steam to which the cloth is exposed as it isalternatively immersed and steamed, and also during the final steamingtreatment in compartment 24 is not a critical aspect of our process.Most conveniently, steam at atmospheric pressure can be employed and atthis pressure is highly effective.

For best results the reducing bath should have a pH in the range 2-3.

The strength of the neutralizing alkali solution employed and the sizeand number of the wash boxes are so selected with respect to the othervariable factors of our process, particularly the speed of travel of thecloth, that the cloth at completion is at a pH in the range 5.5 to 6.0.

We claim:

1. The method of mordanting wool cloth to prepare it for dyeing with amordant dyestufi which consists essentially in continuously'immersingthe undyed and unmordanted cloth in, and squeezing it to completelysaturate it with, a hot aqueous solution consisting essentially of about0.5% of the weight of the solution of an alkyl-arylpolyether alcohol and0.25% to 1.0% of the weight of the solution of a water-soluble chromiumcompound selected from the class consisting of sodium bichromate andpotassium bichromate, continuously reducing the chromium compound to atrivalent chromium compound by passing the wet impregnated cloth into ahot acid bath consisting essentially of between 0.5% and 6.0% of theweight of the bath of hydroxyacetic acid, thereafter continuously andrepeatedly exposing the traveling cloth to steam at atmospheric pressureand immersing it in said acid bath, exposing the traveling cloth tothereafter dyeing the wool with a mordant dye stufi.

2. The method of mordanting wool cloth to prepare it for dyeing with 'amordant dyestuff which consists essentially in continuously im-' mersingthe undyed and unmordanted cloth in, and squeezing it to completelysaturate it with, an aqueous solution at a temperature in the range 70F. to 212 F. and consisting essentially of about 0.5% of the weight ofthe solution of an 'alkylarylpolyether alcohol and 0.25% to 1.0% of theweight of the solution of sodium bichro: mate, continuously reducing thesodium bichromate to a. trivalent chromium compound by pass; ing the wetimpregnated cloth into a hot acid bath at a pH of about 2 to 3, saidbath con} taining between 0.5% and 6.0% of the weight of the bath ofhydroxyacetic acid, thereafter continuously and repeatedly exposing thetraveling cloth to steam at atmospheric pressure and immersing it insaid acid bath, exposing the traveling cloth to steam at atmosphericpressure, continuously passing the cloth through an alkalineneutralizing bath to raise its pH to about 5.5 to 6.0, and thereafterdyeing the wool with a mordant dyestufi.

JOHN N. DALTON. JOHN P. PLOUBIDES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 254,713 Simpson Mar. '7, 18821,492,051 Telen Apr. 29, 1924 1,970,578 Schoeller Aug. 21, 19342,106,634 Greiser Jan. 25, 1938 2,222,285 Ellner Nov. 19, 1940' FOREIGNPATENTS Number Country Date 8,874 Great Britain 1900 9,286 Great Britain1886

1. THE METHOD OF MORDANTING WOOL CLOTH TO PREPARE IT FOR DYEING WITH A MORDANT DYESTUFF WHICH CONSISTS ESSENTIALLY IN CONTINUOUSLY IMMERSING THE UNDYED AND UNMORDANTED CLOTH IN, AND SQUEEZING IT TO COMPLETELY SATURATE IT WITH, A HOT AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF ABOUT 0.5% OF THE WEIGHT OF THE SOLUTION OF ANALKYLARYLPOLYETHER ALCOHOL AND 0.25% TO 1.0% THE WEIGHT OF THE SOLUTION OF A WATER-SOLUBLE CHROMINUM COMPOUND SELECTED FROM THE CLASS CONSISTING OF SODIUM BICHROMATE AND POTASSIUM BICHROMATE, CONTINUOUSLY REDUCING THE CHROMIUM COMPOUND TO A TRIVALENT CHAROMIUM COMPOUND BY PASSING THE WET IMPREGNATED CLOTH INTO A HOT ACID BATH CONSISTING ESSENTIALLY OF BETWEEN 0.5% AND 6.0% OF THE WEIGHT OF THE BATH 